Drug interactions
Amitriptyline + Homatropine
Severity: Moderate
Amitriptyline and Homatropine: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Amitriptyline and homatropine both block muscarinic receptors, so their anticholinergic effects add together. This can produce dry mouth, constipation, urinary retention, blurred vision, tachycardia and confusion, especially in older patients.
What this interaction means in plain words
Amitriptyline and Homatropine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Amitriptyline belongs to Central Nervous System; Homatropine belongs to Genitourinary.
Why it happens
Additive blockade of muscarinic acetylcholine receptors.
What to do
Monitor for anticholinergic toxicity such as urinary retention, constipation and delirium. Reduce doses or use alternatives in older adults and those with glaucoma or prostatic hypertrophy.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Other interactions of Homatropine
- Amantadine + Homatropine Moderate
- Atropine + Homatropine Moderate
- Benztropine + Homatropine Moderate
- Bethanechol + Homatropine Moderate
- Chlorpromazine + Homatropine Moderate
- Clomipramine + Homatropine Moderate
Frequently asked questions
Can I take Amitriptyline with Homatropine?
MediHelp rates the interaction as moderate. Amitriptyline and Homatropine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Amitriptyline and homatropine both block muscarinic receptors, so their anticholinergic effects add together. This can produce dry mouth, constipation, urinary retention, blurred vision, tachycardia and confusion, especially in older patients.
How serious is the interaction between Amitriptyline and Homatropine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for anticholinergic toxicity such as urinary retention, constipation and delirium. Reduce doses or use alternatives in older adults and those with glaucoma or prostatic hypertrophy.
What other medicines interact with Amitriptyline?
MediHelp also lists interactions of Amitriptyline with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Amitriptyline page.
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